Fuses; High-Limit Thermostat; I/O Control Board (Sage); Keypad (For Non-Touch Enabled Ovens) - TurboChef sota Service Manual

52 OVEN SYSTEMS

Fuses

The F1 and F2 fuses are 12-amp, ATMR, class CC.
The F3 fuse is 20-amp, ATMR.
The F1 fuse (via blue wire) and F2 fuse (via brown
wire) are designed to blow if an over-current
situation is encountered by the motor controller,
any cooling fan, either filament transformer, power
supply, or stirrer motor. The F3 fuse is designed
to blow in case of an over-current situation relative
to the microwave system (magnetron, high-voltage
transformer, diode, capacitor).
High Limit Thermostat
The high limit thermostat is a 250 VAC, 3-pole,
manual-reset thermostat with a trip point of 572 º F
(300 º C). The thermostat interrupts power to the
main convection heater in the event of an abnormal
condition. Reset the high-limit thermostat by
pressing the reset button (Figure 38).
Reset
Button
Figure 38: High-Limit Reset Button

I/O Control Board (SAGE)

The I/O control board (SAGE) controls each electri-
cal component of the oven. 24 VDC can be mea-
sured at pin 2 of the J7 connector to confirm control
voltage is being applied (see page 79).

Keypad (For Non-Touch Enabled Ovens)

The keypad is a 8 x 11 matrix membrane switch.
For details on key functions, see page 7.
LED Light Ring (So ˇ ta only)
The LED light ring provides visual cues in regards
to oven operation, and counts down the final 30
seconds of each cook cycle.

Magnetron Thermostats

The magnetron thermostats are "open-on rise."
They are designed to open at 270 º F (132 º C),
which triggers an F5 fault.
NOTE: Except for Single Magnetron Sota Ovens
(where only one magnetron thermostat is used) the
magnetron thermostats are wired in series. If one
opens, the control will switch off both magnetrons
until the open thermostat closes. The thermostats
are self-resetting.

Power Supply

The power supply outputs 24 VDC at 40 watts to
the control board and relays.

Relay - K1 Filament

The K1 relay is a 240 VAC, 24 VDC coil, 20 amp,
sealed single-pole relay. It switches power to the
filament transformers.

Relay - K2 Magnetron Cooling Fans

The K2 relay is a 240 VAC, 24 VDC coil, 20 amp,
sealed single-pole relay. It switches power to the
magnetron cooling fans when the magnetron
filaments are actuated. Power is switched off after
four minutes and fifteen seconds.
NOTE: The four-minute, fifteen-second timer
starts over each time the magnetron filaments are
actuated.

Relay - K3 Stirrer Motor

The K3 relay is a 240 VAC, 24 VDC coil, 20 amp,
sealed single-pole relay. It switches power to the
stirrer motor.

Relay - K6 Voltage

The K6 relay is a 240 VAC, 30 amp, three-pole,
double-throw, 24 VDC relay coil. Operational in
North America only, it switches between 208 and
240 VAC on the HV transformer and filament
transformer taps (depending on incoming voltage).
Through the voltage sensor, the oven defaults to the
240V position and switches to 208 if less than 222
volts is detected. 230V/400V international ovens
and all Japan models utilize the N.C. contacts of the
relay to power the microwave transformers.